Author Topic: MT3 to MT3 adapter?  (Read 1338 times)

Offline PekkaNF

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MT3 to MT3 adapter?
« on: December 23, 2017, 02:50:53 PM »
Problem:
My lathe tail stock has weird taper: needs a draw bar end with a hex socket bolt, drill tang will not fit and without bolt will not eject. great.

I have most of the lathe tail stock tooling with M12 draw bolt arbors, which is pretty nice, because I have MT3 on my milling machine. Some tooling I have simply turned down or cut out the tang. I also have MT2 and Mt1 drill sleeve adapters with mutilated tangs.

But I have got some new MT3 drills and 25/33 mm reamers. These I would like to keep intact on the tail feathers. Specially reamers, in case I would like to sharpen them.

I haven't been able to find a really stubby extension. Most extensions seems to be rather long :Doh:

Any constructive suggestions?

I'm not ready to use that lathe as an achor, because it has MT4 spindle bore.

Pekka

Offline Karlloss

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Re: MT3 to MT3 adapter?
« Reply #1 on: December 24, 2017, 04:06:15 AM »
As you have the lathe and you have existing MT3 tapers, could you not just machine your own sleeve?


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Offline PekkaNF

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Re: MT3 to MT3 adapter?
« Reply #2 on: December 24, 2017, 05:31:40 AM »
It is a possibility, but anyne who had done more of these tapers can comform that they not trivial to make in real world. I was considering of using MT3 to Mt4 reduction sleeve or something..problem is that none of of the ones I have has enough meat. Because the taper is same it needs to be an extension....extension sleeves have ejector slot etc. It looks like there is no no obivious solution.

I removed the whole tail stock and bottom looks like someone had some serious chatter while milling it. Needs least one millimeter milled off from the V:s to bring it to any acceptable bearing. That would explain partly why it has uncertain feel in it.

So, thinking that either new from scrap, extensive rebuild for the old or something like that.

I rummaged trough my drill extensions and I have one OD32 mm parallel part length 315 mm. That should make half decent quill. But it would be some serious work.

Pekka

Offline PekkaNF

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Re: MT3 to MT3 adapter?
« Reply #3 on: December 24, 2017, 04:09:34 PM »
All mating surfaces were pretty bad.


Offline Karlloss

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MT3 to MT3 adapter?
« Reply #4 on: December 24, 2017, 04:20:35 PM »
All mating surfaces were pretty bad.
Just thinking out loud, would it be possible to get a MT3 to MT4 adaptor, I seen them quite cheap, and turn it down to MT3, I understand about the ejection slot, you could machine something to allow this??


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Offline PekkaNF

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Re: MT3 to MT3 adapter?
« Reply #5 on: December 25, 2017, 05:20:17 AM »
Starting to think that tailstock rebuild would be a better option than an adapter.

Which one gets more votes for movement mecanism:
* Trapetzoidal thread
* Rack and pinion - capstan drive?

Pekka

Offline philf

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Re: MT3 to MT3 adapter?
« Reply #6 on: December 25, 2017, 09:54:54 AM »
Starting to think that tailstock rebuild would be a better option than an adapter.

Which one gets more votes for movement mecanism:
* Trapetzoidal thread
* Rack and pinion - capstan drive?

Pekka

The nicest lathe I've ever seen was a Schaublin 125 in our toolroom. It had a 2-speed rach and pinion feed. One was diect from the handwheel to the pinion, the other had some sort of gearing between the two (epicyclic?). I tried to but the lathe when our toolroom closed but I didn't bid quite enough!

Phil.
Phil Fern
Location: Marple, Cheshire

Offline RotarySMP

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Re: MT3 to MT3 adapter?
« Reply #7 on: December 25, 2017, 03:37:54 PM »
Stefan Gotteswinter did a tailstock like that Schaublin...
http://www.gtwr.de/shop/pro_mykrodreh/tailstock.html
Mark

Offline PekkaNF

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Re: MT3 to MT3 adapter?
« Reply #8 on: December 26, 2017, 01:12:14 AM »
Thank you. That Schablin picture is very inspirational.

Thank you Mark, that link uses the tailstock that  is actually very close the same I have.

Pekka